Circles

1. The angle in a semi circle is 90°

2. Angles in the same segment are equal

3. Angle at the centre is twice the angle on the circumference

4. A tangent meets a radius at 90°

5. Two tangents to a circle from the same point are equal

6. Opposite angles of a cyclic quadrilateral* add up to 180°

7. The perpendicular bisector of any chord goes through the centre of a circle

8. Alternate segment theorm - the angle between a tangent and a chord to the angle in the opposite segement

*cyclic quadrilateral means all 4 vertices are on the circumference